Bus strips and contacts

ABSTRACT

An electrical contact for use in a card-edge connector has a nose portion with a bifurcated section comprising a pair of legs separated by a bifurcating slot. At least one chamfered surface is coined into the contact below the bifurcating slot, and a bus strip is provided with a similar chamfered surface for mating with the chamfered surface on the contact when the bus strip is inserted into the bifurcating slot. In an alternative embodiment of the invention, a slit, defined in part by four chamfered surfaces, is provided in the tail portion of the contact, and the bus strip is inserted into the slit so that the chamfered surfaces of the bus strip mate with the chamfered surfaces on the tail portion of the contact. A further embodiment of this invention comprises a card-edge contact which has flat, parallel, uncoined surfaces below the bifurcating slot, and a bus strip which has a contact-receiving slot defined, in part, by inwardly facing projections having contact-engaging surfaces thereon. The bus strip is inserted into the bifurcating slot of the contact with the flat, parallel, uncoined surfaces of the contact positioned within the contact-receiving slot of the bus strip.

United States Patent [72] Inventor Thomas J. Stokes Philadelphia, Pa.[21] Appl. No. 815,772 [22] Filed Apr. 14, 1969 v [45] Patented Sept.28, 1971 [73] Assignee Elco Corporation Willow Grove, Pa.

Continuation-impart of application Ser. No. 759,343, Sept. 12,1968, nowPatent No. 3,562,805.

54 BUS sraii s AND CONTACTS 4 Claims, 10 Drawing Figs.

[52] US. Cl ..339/l76 MP, 339/22 B [51] Int. Cl H05k 1/07 [50] FieldofSearch 339/17 L, 17 LM,17 M, 18,47, 176 M, 176 MP, 217, 258, 273,22B;317/101 CE 3,112,147 11/1963 Pferd et a1. 339/97 3,287,686 11/1966Ruehlemann 33 /l 7 3,431,545 3/1969 Kirby 339/258 3,434,094 3/1969Walter 339/17 Primary Examiner- Ernest R. Purser Assistant ExaminerLawrence .1. Staab Attorney-D. R. Pressman ABSTRACT: An electricalcontact for use in a card-edge connector has a nose portion with abifurcated section comprising a pair of legs separated by a bifurcatingslot. At least one chamfered surface is coined into the contact belowthe bifurcating slot, and a bus strip is provided with a similarchamfered surface for mating with the chamfered surface on the contactwhen the bus strip is inserted into the bifurcating slot. In analternative embodiment of the invention, a slit, defined in part by fourchamfered surfaces, is provided in the tail portion of the contact, andthe bus strip is inserted into the slit so that the chamfered surfacesof the bus strip mate with the chamfered surfaces on the tail portion ofthe contact, A further embodiment of this invention comprises acard-edge contact which has flat, parallel, uncoined surfaces below thebifurcating slot, and a bus strip which has a contact-receiving slotdefined, in part, by inwardly facing projections having contact-engagingsurfaces thereon. The bus strip is inserted into the bifurcating slot ofthe contact with the flat, parallel, uncoined surfaces of the contactpositioned within the contact-receiving slot of the bus strip.

. PATENTEDSEPBBIQII I 3.609550 SHEET 1 [1F 3 INVEN THOM .STOKES BYfldzvv ,4/

ATTORNEY.

PATENTEDSEPZBIQII 3,609,650

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INVENTOR.

THOMAS J. STOKES ATTORNEY.

PATENTED SEP28 l9?! SHEET 3 UF 3 0 7///////// 7H /0 I V v m 4 DINVENTOR. BY THOMAS J. STOKES ATTORNEY.

BUS STRIPS AND CONTACTS This application is a continuation-in-part of myapplication filed Sept. 12, 1968, now U.S. Pat. No. 3,562,805, grantedFeb. 9, 1971 This invention relates to the mechanical and electricalinterconnection of contacts with bus strips.

In electronic equipment groups of printed circuit boards carryingvarious circuit components are frequently interconnected to provideelectrical circuit systems. In one interconnection system, each printedcircuit board is plugged into an electrical connector which is mountedon the front face of a metal plate. The metal plate provides a groundplane for the electrical circuits on the printed circuit boards as wellas a mechanical support for the assembled printed circuit boards andconnectors.

Each connector is comprised of a casing of insulating material in whichare mounted a plurality of contacts. Each contact has a tail sectionthat passes through and extends beyond the rear face of the metal plateupon which the connector is mounted. The tail sections of the contactsare usually square or rectangular in cross section for permittingconventional automatic back panel wiring techniques, such as solderlesswrapping or the like, to be used to establish the required electricalinterconnections and to permit power and signal inputs to be applied tothe network and to permit signal outputs to be taken therefrom.

ln apparatus of the type described, each printed circuit board generallyrequires one or more power inputs, and for this purpose a voltage busassembly is provided. A voltage bus assembly is comprised of a pluralityof electrically interconnected contacts which mate with those conductivepads on the printed circuit boards, which require power at the samevoltage level.

One type of voltage bus assembly is disclosed in the U.S. Pat. ofRuehlemann/Slobodzian, No. 3,559,604. issued 2/2/71, and assigned to thepresent assignee. This voltage bus assembly is manufactured as a unitarystructure by passing a continuous strip through a progessive die in thedirection of the longitudinal axis of the strip. The nose portions ofthe various contacts are stamped from a portion of the strip on one sideof the longitudinal axis, and the tall portions are stamped from aportion of the strip on the other side of the longitudinal axis. Thecenter section of the strip provided the electrical and mechanicalinterconnection between the various nose and tail portions. Tolerancevariations in the manufacture of the bus assembly, and the insulatingcasings adapted to receive the bus assembly present alignment problemsin the assembling operation. The unitary construction of the busassembly permits only limited pivotal movement between the nose and tailportions of such assembly on the one hand, and the bus strip of theassembly on the other hand. This limited movement, accompanied by thefact that automatic assembly equipment presently is not available, makesthe alignment and assembly of the bus assembly with the insulatingcasing a difficult, timeconsuming operation.

Another disadvantage of the bus assembly shown in said Ruehlemann et al.applications is its lack of versatility. Because of the unitaryconstruction of the bus assembly, any defect or operational failure of asingle nose portion or tail portion necessitates replacement of thecomplete unitary structure. The complete replacement of the bus assemblyinvolves a waste of material, and is difficult to effect because of thelarge number of nose and tail portions which must be removed from andreassembled with the insulating casing.

A bus assembly comprised of individual contacts and a separate bus stripis known. This assembly is comprised of a card-edge contact having anose portion comprised of a pair of legs separated by a bifurcatingslot. Immediately below and adjacent to the termination of the slot, alaterally extending clip is provided with a pair of opposed clampingfingers which will electrically and mechanically engage a fiat,electrically conductive strip inserted into the bifurcating slot of thecontact. These clip extensions on the contacts limit the minimum spacingbetween adjacent contacts. In fact, such contacts were designed for usein a bus assemblies wherein adjacent contacts are spaced on 250- inchcenters or greater. This spacing positioned in separate, adjacent,single readout connectors; however, in dual readout connectors whereinadjacent contacts are spaced as close as 0.100 inch, contacts with clipextensions are not acceptable. For purposes of definition in thisapplication, a single readout connector" is defined as one havingcontacts positioned on only one side of a circuit board receiving slotfor electrically engaging conductive tracks on only one side of acircuit board, and a dual readout connector" is defined as one havingcontacts on both sides of a circuit board receiving slot forelectrically engaging conductive tracks on both sides of a circuitboard.

To accommodate the clip extensions, the contacts are stamped from stripmaterial on approximately 0.5-inch centers, whereas contacts withoutclip extensions are stamped on less than 0.25-inch centers. Thus, morewaste is encountered in manufacturing contacts with clip extensions thanis the case in manufacturing contacts without such extensions.

The bus assemblies of the present invention also comprise separatecontacts and bus strips, thus eliminating the main assembly difiicultiesencountered in utilizing the unitary bus assembly disclosed in saidRuehlemann et al. application. Moreover the contacts of this inventiondo not have clip extensions and therefore the assembly of the presentinvention can be utilized in dual readout connectors wherein contactspacings as small as 0.100 inch may be required. Also, the problem ofexcessive waste of material is alleviated through the elimination of theclip extensions.

One bus assembly of the invention of the parent case hereof utilizescontacts which have a nose portion and a tall portion interconnected bya body portion. The body portion is utilized to firmly retain theelectrical connector. The nose portion is defined by a bifurcatedsection comprises a pair of legs separated by a bifurcating slot. Eachleg has a front surface with a curved portion thereof adapted to engageto a conductive track of a circuit board when the circuit board ispositioned within a circuit board receiving slot in the insulatingcasing of an electrical connector.

The bifurcating slot extends downwardly from an upper surface of thenose section of the contact and terminates short of the body portion ofsaid contact. An elongated slit is in alignment with the axis of theslot and is positioned in a section of the contact which is disposedbetween the body portion of the contact and the termination of the slot.Chamfered surfaces are provided on the contact adjacent the slit. Anelongated bus strip is provided with contact-receiving slots extendingthrough the lower surface thereof in a perpendicular direction to thedirection of elongation of the strip, and chamfered surfaces areprovided on the bus strip adjacent the contactreceiving slots forengaging the chamfered surfaces on the contacts when the bus strip isinserted into the bifurcating slots of such contacts. The matingchamfered surfaces provide excellent electrical and mechanicalinterconnections between the contacts and bus strip.

In a second embodiment of the invention of the parent case thereofcontacts are utilized which have the same general configuration as thecontacts utilized in the first embodiment with the exception that theslit and chamfered surfaces are omitted. The region of the contactbetween the body portion and the termination of the bifurcating slot iscomprised of a pair of flat, substantially parallel, uncoined surfaces.An elongated bus strip is provided with contact-receiving slotsextending through the lower surface thereof in a perpendicular directionto the direction of elongation of said strip. The inner surfacesdefining each slot are comprised of contact-engaging surfaces whichdefine a gap therebetween. The contact engaging surfaces on the busstrip engage the flat surfaces in the contacts when the bus strip isinserted into the bifurcating slots of such contacts.

- The more important features of this invention have thus been outlinedrather broadly in order that the detailed description thereof whichfollows may be better understood, and in order that the contribution tothe art may be better appreciated. There are, of course, additionalfeatures of the invention that will be described hereinafter and whichwill also form the subject of the claims appended hereto. Those skilledin the art will appreciate that the conception upon which thisdisclosure is based may readily be utilized as a basis for designingother structures for carrying out the several purposes of thisinvention. It is important, therefore, that the claims to be grantedherein shall be interpreted with sufficient breadth to prevent theappropriation of this invention by those skilled in the art.

DRAWINGS FIG. 1 is a perspective view of a novel contact;

FIG. 2 is a front view of one embodiment of the bus strip of thisinvention;

FIG. 3 is an assembly view of the contacts in an insulating casing; suchcontacts being interconnected by the bus strip of this invention, and asection of one of the contacts being removed to show details ofconstruction;

FIG. 4 is a sectional view taken through line 4-4 of FIG. 3;

FIG. 5 is an assembly view, similar to FIG. 3, of a second embodiment;

FIG. 6 is a sectional view taken through line 66 of FIG. 1;

FIG. 7 is a perspective view of a contact utilized in the embodiment ofthis invention;

FIG. 8 is a sectional view taken through line 8-8 of FIG. 7;

FIG. 9 is a view of the retaining member as viewed from the right ofFIG. 10; and

FIG. 10 is an assembly view, similar to FIG. 3, of the embodiment ofthis invention.

Referring now to the drawings, FIG. 1 shows a perspective view of acontact comprising a nose portion 12 and a tail portion 16interconnected by a body portion 14. The nose portion 12 has abifurcated section comprising a pair of legs 18 (front leg partially cutaway) separated by a bifurcating slot 19. The bifurcating slot 19terminates at 23, and a slit 21 extends downwardly therefrom inalignment with the axis of slot 19. The slit 21 terminates in a bridgingportion 28 which is adjacent body portion 14 of the contact. Each leg 18is provided with a rear surface 22,'an inner surface 24, and a frontsurface 20. The front surface 20 has a curved circuit board-engagingportion 32 for engaging the conductive track of a printed circuit board.Regions of the contact adjacent slit 21 are coined to form fourchamfered surfaces 26 (FIGS. 1, 4, and 6). The bridging portion 28 atthe end of slit 21 is comprised of comprised of chamfered surfaces 30(FIGS. 1 and 2). The slit 21 need not be a through slit but can be as ablind slit.

The body portion 14 of the contact is utilized to retain the contact 10within insulating housing 72 of an electrical connector 70 (FIG. 3). Thetail portion 16 of the contact is comprised of a straight post portionwhich is suitable for automatic wire wrapping or other solderless-typeconnections. It is understood that other suitable terminations can beprovided on the contact of this invention.

Referring now in detail to FIGS. 2, 3, and 4, a bus strip 40 isdisclosed which will mate with contact 10. The bus strip 40 is comprisedof elongated, substantially parallel, side surfaces 54 which areinterconnected by an upper surface 42 and a lower surface 44. Aplurality of contact-receiving slots 46 extend through the side surfaces54 of the strip 40 from the lower surface 44 toward the upper surface 42in a perpendicular direction to the direction of elongation of said sidesurfaces 54.

The contact-receiving slots 46 are defined, in part, by inner surfaces52 which face each other and are disposed in planes that aresubstantially perpendicular to the planes of the side surfaces 54. Theinner surfaces 52 and side surfaces 54 are interconnected by chamferedsurfaces 48 which are adapted to mate with the chamfered surfaces 26 ofcontact 10. The inner surfaces 52 and chamfered surfaces 48 terminateshort of lower surface 44 of the bus strip 40, and inclined surfaces 50interconnect said chamfered surfaces and inner surfaces with lowersurface 40.

A relief slot 56 is interposed between each pair of contactreceivingslots 46. These relief slots extend through the side surfaces 54 of thebus strip 40 and are parallel to contactreceiving slots 46. Each reliefslot 56 and its adjacent contactreceiving slot 46 defines a leg 58therebetween which is resiliently deflectable in the plane of the busstrip 40 to provide a resilient interconnection between contact 10 andbus strip 40. Relief openings 62- are provided at the end of reliefslots 56 remote from lower surface 44 to further contribute to theresiliency of legs 58. Since legs 58 are resiliently deflectable, thebus strip can be assembled easily with contacts which are mounted withininsulating casings despite some slight misalignment of parts due totolerance variations.

FIG. 4 shows the manner in which the chamfered surfaces 48 of the busstrip 40 mate with chamfered surfaces 26 of the contact 10. The busstrip 40 is inserted into the bifurcating slot 19 of the contacts 10with each contact-receiving slot 46 aligned with a respective slot 21 ineach of the contacts. The bus strip 40 is then pressed downwardly tocause chamfered surfaces 48 on the bus strip to frictionally engagewith, and slide against chamfered surfaces 26 of the contact. Thesliding, frictional engagement between the four chamfered surfaces oneach contact 10 and the corresponding surfaces on the bus strip 40 willremove any oxide built up between such surfaces to insure thatelectrical continuity will exist.

In the undeflected condition of lets 58, the distance between facinginner surfaces 52 defining each contactreceiving slot 46 is smaller thanthe the transverse dimension of the contact in the region of the slit 21and chamfered surfaces 26. This arrangement causes adjacent legs 58 tobe resiliently urged apart upon assembly of the bus strip 40 withcontact 10 to insure that excellent mechanical and electrical continuityis maintained.

In assembled condition, clearance is provided between inclined surfaces50 on bus strip 40, and the chamfered surfaces 30 on each contact 10 toprevent adjacent legs 58 from being forced apart due to the slidinginteraction between said surfaces, which would thereby destroy theelectrical and mechanical continuity between the chamfered surfaces ofbus strip 48 and contact 10.

FIG. 3 shows an electrical connector 70 which has a pair of contacts 10therein which has a pair of contacts 10 therein which are interconnectedby bus strip 40. The electrical connector 70 is comprised of insulatinghousing 72 and a plurality of pairs of contacts 10 (only one pair beingshown in FIG. 3); the insulating housing being mounted to a metal platethrough any suitable connection means such as hubs on said insulatingcasing. Slots are provided through sidewalls 73 of the insulator toreceive the bus strip therein. The circuit board may have circuitry onopposite sides thereof. Electrical terminations to both sides of thecircuit board are effected by each pair of contacts 10 in insulatinghousing 72. The bus strip for electrically interconnecting the pair ofcontacts 10 shown in FIG. 3 is provided with contact-receiving slots 46which are spaced the same distance across the strip as the spacingbetween such contacts 10. The contact spacing between each pair ofcontacts 10 in a dual readout connector is usually between 0.100 inchand 0.002 inch.

It is understood that usually a plurality of electrical connectors aremounted side by side on metal plate 80 with sidewalls 73 adjacent to oneanother, and the slots in said sidewalls being aligned to receive thebus strip 40 in a plane which is substantially perpendicular to thecircuit board receiving slots 76 to thereby electrically interconnectcontacts within each electrical connector which require power at thesame voltage level.

Referring now to FIG. 5, a contact 10A has a nose portion comprised of apair of legs separated by a bifurcating slot as described with respectto the contact disclosed in FIG. 1. The

' region of the nose portion of contact 10A which is between the bodyportion of said contact and the termination of the bifurcating slot iscomprised of a pair of flat, substantially parallel, surfaces 94 whichare neither slit nor coined.

The bus strip 40A which is utilized to interconnect contacts A iscomprised of elongated, substantially parallel, side surfaces 54A whichare interconnected by a lower surface 44A. A plurality ofcontact-receiving slots 46A are spaced along the bus strip in thedirection of elongation of said bus trip on the same spacing as thespacing between the contacts to be interconnected. Eachcontact-receiving slot 46A extends through the said surfaces 54A in aperpendicular direction to the direction of elongation of said busstrip. Each slot is defined, in part, by inner flat surfaces 88, whichface each other, and which terminate short of the lower surface 44A.lnwardly facing projections 90 on strip 40A have contact-enagingsurfaces 48A thereon defining a gap therebetween; the distance betweenthe contact-engaging surfaces 48A being less than the transversedimension between the flat, parallel surfaces 94 of contact 10A. A pairof relief slots 56A are positioned between each pair ofcontact-receiving slots 46A; one of said relief slots 56A forming a leg58A with its adjacent contactreceiving slot 46A, and the other reliefslot 56A forming a leg 58A with its adjacent contact-receiving slot 46.The arrangemerit of relief slots as shown in bus strip 40A can also beutilized with the bus strip 40, and the arrangement of relief slots 56shown in bus trip 40 can also be utilized in the bus strip 40A. The busstrips have the versatility of being utilizable with either dual readoutconnectors, single readout connectors, or a combination of both types ofconnectors, single readout connectors, or a combination of both types ofconnectors.

The bus strip 40A is connected to contacts 10A in the same manner as busstrip 40 is connected to contact 10. Since the gap betweencontact-engaging surfaces 48A on the bus strip is less than thetransverse dimension between the flat, substantially parallel surfaces94 of the contact 10A, adjacent legs 58A will be biased apart by theirengagement with the flat surfaces 94 to thereby provide a resilientelectrical and mechanical interconnection with the contact.

The first two voltage bus assemblies described. The loose contacts 10 or10A are first assembled into the insulating housings 72 of theelectrical connectors 70. The insulating housings 72 loaded withcontacts 10 or 10A are then assembled on metal plate 80. Both theloading of the contacts within insulating housings 72, and theassembling of the the electrical connectors 70 on the metal plate areaccomplished by wellknown, timeproven techniques and automaticequipment. After the electrical connectors are mounted on the metalplate, the bus strips 40 or 40A are inserted into the slots formed inthe sidewalls 73 of the insulating casings 72 through the bifurcatingslots of the contacts which are to be electrically interconnected, untilcontact-receiving slots 46 or 46A of the bus strip 40, 40A,respectively, are directly aligned with the bifurcating slots of thecontacts. The bus strips 40 or 40A are then pushed downwardly toward thetail portion of the contacts to cause the legs 58 or 58A to electricallyand mechanically engage with the contacts 10, 10A, respectively.

Referring now to FIGS. 7-10, the embodiment of the present case isshown. An elongated tail portion 163 (FIGS, 7 and 8) of the contact isbifurcated in the direction of elongation, by a slit 218. The slit2lB-is defined in part by four elongated chamfered surfaces 263 (FIG.8). Slit 21B terminates in a base which is defined in part by chamferedsurfaces 308. The nose portion and body portion of the contact can be ofany desired configuration; however, the slit tail configuration isideally suited for making a bus connection between contacts having anonbifurcated nose portion.

The bus strip 403 which is utilized in making the bus connection to thecontact tail portions of the contacts is identical with the bus strip 40shown in FIG. 2.

To make the bus connections, loose contacts are first assembled into aninsulating housing 728 to form electrical connectors. The electricalconnectors are then inserted into metal plate 80 in side by siderelationship with the slit tail portion 168 of each contact extendingbelow the bottom surface of the plate. The slits in the tail portions ofthe contacts which are to be electrically interconnected lie in a commonplane, and bus strip 408 is inserted into such slits. Chamfered surfaces48B on the bus strip frictionally, electrically, and mechanically engagechamfered surfaces 268 on the tail portions.

To insure that the bus strip 408 does not separate from the contacttails 16B, and that the bus strip is properly positioned with respect tothe contact tails, at least one retaining member 100 is provided. Theretaining member has a bifurcated upper holding portion 102 defined by apair of resilient legs 104. The outer periphery of the holding portionis provided with a slot 106 defining locking shoulders for engaging andholding the retaining member 100 has a bus strip receiving cavity 112therein which is defined by resilient bus strip-retaining finger 108having flanged lower sections 110 and an upper surface 114 having apositioning and stabilizing groove 116 formed therein. As bus strip 40is inserted into slits 218 provided in the tail portions 168, the busstrip urges the resilient bus strip retaining fingers 108 apart, untilend surface 428 of the bus strip firmly seats against the base 116 ofthe positioning and stabilizing groove 116. In this position, the lowersurface 448 of the bus strip 408 is positioned above the upper surfacesof flanged lower section 110 to permit bus strip retaining fingers 108to return to their normally closed position. In this condition, the busstrip 40B is retained within bus strip receiving cavity 112, therebypreventing the bus strip from becoming separated from the tail portions168. Furthermore, when end surface 423 of the bus strip is in engagementwith the base 116 of the positioning and stabilizing groove 116, the busstrip is properly positioned with respect to the tail portions 168. Inthe assembled condition, inclined surfaces 508 provided on bus strip 40Bdo not engage the chamfered surfaces 308 of the tail portions. Suchengagement could cause fingers 588 to be urged outwardly therebyimpairing the electrical and mechanical connection between the chamferedsurfaces 26B and chamfered surfaces 488 provided on the bus strip.

in FIG. 9, one retaining member 100 is shown positioned within anopening in metal plate which is adjacent one longitudinal end of the busstrip 403; however, it is within the scope of this invention to providea pair of retaining members for each bus strip 408 with each retainingmembers being positioned in an opening in metal plate 80 aligned with alongitudinal end of the bus strip.

1 claim:

I. An electrical interconnection system comprising a. a plurality ofelongated electrical connectors mounted side by side on a supportingstructure, each electrical connector having a longitudinally extendingcircuit board-receiving slot the longitudinal axis of each circuitboard-receiving slot being parallel to the direction of elongation ofits corresponding electrical connector; at least one electrical contactdisposed in each of two of said electrical connectors, each contacthaving a nose portion, an elongated tail portion, said nose and tailportions being interconnected by a body portion;

the tail portion of each contact being bifurcated in its direction ofelongation by a slit which is defined, in part, by chamfered surfaces,said contacts being oriented such that said slits lie about a planewhich is substantially perpendicular to said circuit board-receivingslots; and

d. a substantially fiat elongated bus strip positioned within the slitsin the tail portion of each contact, said bus strip having chamferedsurfaces which frictionally engage the chamfered surfaces on saidcontacts.

2. The electrical interconnection system of claim 1, wherein each tailportion is provided with a pair of elongated chamfered surfaces on eachside of the slit, said chamfered surfaces being elongated in thedirection of elongation of said tail portion, said bus strip havingsubstantially parallel elongated side surfaces and an end surfaceinterconnecting said side surfaces, contact-receiving slots extendingthrough said side surfaces from the end surface in a directionperpendicular to the direction of elongation of said side surfaces, eachcontact receiving slot being defined, in part, by a pair of chamferedsurfaces one each side of said contact-receiving slot, the chamferedsurfaces on said bus strip frictionally engaging the respectivechamfered surfaces on the tail portion of contact.

3. The electrical interconnection system of claim 2 wherein a retainingmember is mounted within an opening in said supporting structure, saidretaining member being positioned adjacent one longitudinal end of saidbus strip and having means

1. An electrical interconnection system comprising a. a plurality ofelongated electrical connectors mounted side by side on a supportingstructure, each electrical connector having a longitudinally extendingcircuit board-receiving slot, the longitudinal axis of each circuitboard-receiving slot being parallel to the direction of elongation ofits corresponding electrical connector; b. at least one electricalcontact disposed in each of two of said electrical connectors, eachcontact having a nose portion, an elongated tail portion, said nose andtail portions being interconnected by a body portion; c. the tailportion of each contact being bifUrcated in its direction of elongationby a slit which is defined, in part, by chamfered surfaces, saidcontacts being oriented such that said slits lie about a plane which issubstantially perpendicular to said circuit board-receiving slots; andd. a substantially flat, elongated bus strip positioned within the slitsin the tail portion of each contact, said bus strip having chamferedsurfaces which frictionally engage the chamfered surfaces on saidcontacts.
 2. The electrical interconnection system of claim 1, whereineach tail portion is provided with a pair of elongated chamferedsurfaces on each side of the slit, said chamfered surfaces beingelongated in the direction of elongation of said tail portion, said busstrip having substantially parallel elongated side surfaces and an endsurface interconnecting said side surfaces, contact-receiving slotsextending through said side surfaces from the end surface in a directionperpendicular to the direction of elongation of said side surfaces, eachcontact receiving slot being defined, in part, by a pair of chamferedsurfaces on each side of said contact-receiving slot, the chamferedsurfaces on said bus strip frictionally engaging the respectivechamfered surfaces on the tail portion of each contact.
 3. Theelectrical interconnection system of claim 2 wherein a retaining memberis mounted within an opening in said supporting structure, saidretaining member being positioned adjacent one longitudinal end of saidbus strip and having means for retaining said bus strip to prevent saidbus strip from separating from said contacts.
 4. The electricalinterconnection system of claim 3 wherein a second retaining member ismounted within an opening in said supporting structure adjacent the endof said bus strip opposite said one longitudinal end, said secondretaining member having means for retaining said opposite longitudinalend to further support said bus strip.